I have a custom Firefox add-on. It worked ok, until we decided to make it self update-able.
According to manuals at mozilla.org, there should be an
<em:updateURL> entry in add-on's install.rdf, containing a link to some update.rdf. Seems pretty simple.
But, when I add
<em:updateURL>some_url</em:updateURL>, the add-on doesn't work. I use Netbeans IDE with Foxbeans plugin for development, and when I run add-on project from this IDE, Firefox runs with this add-on switched off (and switching on disabled). When I compile the XPI and add it to Firefox (3.6.12), it says about version incompatibility and doesn't work either. Doesn't matter, if I use http or https in the updateURL.
If this tag is empty, like this:
<em:updateURL></em:updateURL> , everything works (but doesn't update itself, of course)
The solution was quite simple, though not obvious at a first glance.
<em:updateURL> should be after
<em:targetApplication>, not before.
Hope this would help somebody, sometime.